Apparatus for detection of phosphorus or sulfur containing vapors or aerosols

ABSTRACT

A hydrogen burner capable of detecting phosphorous and sulfurbearing vapors and aerosols. The burner is a block of aluminum with borings within forming burning chambers and a flame channel. The air sample and hydrogen gas are drawn through at a high velocity which requires burning in a first chamber to eliminate the excess oxygen and then a second burning near a narrow flame channel, the flame being drawn into the flame channel and the reducing portion thereof being observable through a viewing port. The burner is cooled by a water-circulating system. The air contaminant is detected by utilizing the chemiluminescence phenomenon. The light emitted by the reducing portion of the flame is passed through a two-color (blue and green), rotatory, color filter which allows pulses of different intensity to strike a phototube. The difference in intensity is amplified and used to activate some type of indicator or alarm.

United States Patent 1 1 Haas [ Apr. 15, 1975 APPARATUS FOR DETECTION OFPHOSPHORUS 0R SULFUR CONTAINING VAPORS OR AEROSOLS [75] Inventor: EdwardC. Haas, Rapid City, S.

Dak.

[73] Assignee: The United States of America as represented by theSecretary of the Navy, Washington, DC.

[22] Filed: Feb. 21, 1968 [21] Appl. No.: 707,926

[58] Field of Search 23/254, 255, 232, 230 PC, 23/253 PC; 250/71; 88/14SE; 356/87, 187;

3,807,863 4/1974 Raillere et al. 431/126 X Primary Examiner-Benjamin R.Padgett Assistant ExaminerE. A. Miller Attorney, Agent, or Firm-RichardS. Sciascia; Arthur A. McGill; Prithvi C. Lall [57] ABSTRACT A hydrogenburner capable of detecting phosphorous and sulfur-bearing vapors andaerosols. The burner is a block of aluminum with borings within formingburning chambers and a flame channel. The air sample and hydrogen gasare drawn through at a high velocity which requires burning in a firstchamber to eliminate the excess oxygen and then a second burning near anarrow flame channel, the flame being drawn into the flame channel andthe reducing portion thereof being observable through a viewing port.The

431/4, 126 burner is cooled by a water-circulating system.

The air contaminant is detected by utilizing the [56] References C'tedchemiluminescence phenomenon. The light emitted UNITED STATES PATENTS bythe reducing portion of the flame is passed through 2,203,036 6/1950 VanBriessen et al 88/14 a two-color (blue and g rotatory. color filter3,174,393 3/1965 Dewey et al. 88/14 which allows pulses of differentintensity to strike a 3,213,747 10/1965 Van Der Smissen 23/232phototube. The difference in intensity is amplified and 3,239,311Luehrmann 8t 31. 23/254 used to activate some type of indicator or alarm3,428,401 2/1969 Buzza 356/187 3,489,498 1/1970 Brody et a1. 356/187 7Claims, 7 Drawing Figures F.%7PAE//p P40707085 65 l l o 60 keMoTe flMFA$76K [Na/6'97? i Pan/5 SUPPLY :3"

[Now/170R APPARATUS FOR DETECTION OF PHOSPI-IORLS OR SULFUR CONTAININGVAPORS OR I AEROSOLS The invention described herein may be manufacturedand used by or for the Government ofthe United States of America forgovernmental purposes without the payment of any royalties thereon ortherefor.

This invention relates to means for detecting airborne contaminantelements which emit characteristic colors while burningchemiluminescently and especially to such means which utilizes a novelreducing burner.

Military and naval activities have an interest in the detection ofpoisonous gases. especially the vapors or aerosols of phosphorusorsulfur-containing compounds. Various methods of detection are possiblebut do not meet the stringent requirements for high stability.reliability and resistance to extreme environmental conditions such asshock. vibration. and atmospheric conditions which may occur in thenaval service. for example.

One method of detecting the presence of a chemical element such asphosphorus or sulfur is by means of the color spectrum it emits when itis burned. Phosphorus and sulfur (in addition to some other elements)exhibit the phenomenon of chemiluminescence when exposed to freeradicals in a hydrogen-rich flame. The emission spectrum for hydrogenshows approximately equal emission in blue and green light; that forphosphorus is higher in green than in blue; and that for sulfur ishigher in blue than in green.

Problems which must be solved in the ordinary burner when it is employedunder harsh naval conditions include reduction of background light whichinterferes with the detection of low concentrations of phosphorus andsulfur. reduction of flame flicker which sets the detection sensitivityat a level not lower than the highest background level and stabilizationof the flame against sudden pressure changes such as those caused byshell blasts.

An object of this invention is to provide a burner capable of being usedto detect airborne contaminant elements such as phosphorus and sulfur.said burner being reliable. insensitive to sudden pressure changes andrapid and sensitive in its detection of the contaminant elements.

The objects and advantages of this invention are accomplished by adetection system which utilizes a hydrogen burner in which the velocityof the gases. the flame temperature and the level of background lightare carefully controlled to provide the desired results. A viewing port.placed at the proper point in the flame channel. permits the flame to beviewed. The light emitted by the flame is choppedby a rotating opticalfilter of two different colors and the difference in intensity of thefiltered colors is utilized to provide an indication of the presence ofthe sought-for contaminant in the air sample.

Other objects and advantages will appear from the following descriptionof an example of the invention. and the novel features will beparticularly pointed out in the appended claims.

In the accompanying drawings:

FIG. I is an isometric illustration of the reducing burner;

FIG. 2 is a schematic showing of a cross-sectional side view of theburner of FIG. I taken vertically through the viewing port.

FIG. 3A is a mechanical drawing showing the construction of the lowertwo sections of the burner:

FIG. 3B is a mechanical drawing showing a top view of FIG. 3A:

FIG. 4 is a bottom view of the rectangular section which fits over theviewing port of the burner:

FIG. 5 is a schematic showing the detection system components: and

FIG. 6 is an isometric illustration of a burner which can be used tosimultaneously detect both phosphorusand sulfur-bearing aircontaminants.

The phenomenon of chemiluminescence. which is the emission of light whencertain chemical elements burn in a hydrogen-rich flame. can be used todetect the presence of these elements-by utilizing the colors of theemitted light. Both phosphorus and sulfur chemiluminescence. Carbon andhydrogen give emission spectrograms comparable to sulfur in dispersionbut far lower in intensity. About 1000 times as much carbon is requiredto equal the emission given by phosphorus and the maximum amount ofhydrogen which will burn in air produces a flame luminance merely equalto the signal produced by phosphorus at a concentration of 0.01micrograms per liter of air burned.

There is a difference in intensity of emission of blue and green lightby phosphorus. the intensity of the green light being greater than thatof the blue (for sulfur. the reverse is true). This difference inintensity permits detection of the presence of vaporous or aerosolicphosphorus or phosphorus-bearing compounds in the air. as will beexplained hereinafter in connection with FIG. 5. I

The reducing burner I0 which is used is shown in FIG. I. It consists ofa substantially rectangular. rigid block which may be made of aluminum.for example. The block is sectioned for ease of assembly and disassemblyand for ease of boring. There is in the top section an air inlet(sample-in) port 12., a hydrogen inlet (hydrogen-in) port 14 and a wateroutlet (water-out) port 16. The middle section contains anignitorelectrode port 18. The bottom section contains a water inlet(water-in) port 20 and a gas exhaust port 22. It also contains a viewingport 24 formed by undercutting the front of the rectangular block downto the flame channel connecting the hydrogen-in port 14 with the exhaustport 22.

The burner comprises a first-stage burner and a second-stage burner. Thefirst stage burner can be considered to include a wide first-burnerinlet channel 32 through which hydrogen is drawn from the left (see FIG.2) and air from the right. the burner chamber 34 and a narrowfirst-burner exhaust channel 36. Arrows show the direction of gas flowin these channels.

The second-stage burner can be considered to include the second-burnerchamber 38 the bottom of which includes a boring in which the ignitorelectrode 18 is located. the narrow flame channel 26 and the exhaustchamber 40.

A water channel 42 connects the water-in port 20 to the water-out port16.

FIGS. 3A and 3B are mechanical drawings showing the bottom two sectionsof the reducing burner in front and top view. respectively. The viewshown in FIG. 3A is a 90 clockwise rotation of the view shown in FIG. 2.

The rectangular viewing-port cover 44 for the undercut portion of thereducing burner is shown in bottom view (i.e.. the side shown is thatwhich fits into the undercut) in FIG. 4. A rubber gasket 46 encloses thecir cumference of an oval-shaped pane .of glass or window 48 and theseare glued or otherwise fastened to the cover 44. The gasket 46 fits intothe oval undercut 30 so that the viewing port 24 is covered by the glasswindow 48.

The problems encountered in designing this burner to obtain the requiredcharacteristics are solved by rapid mechanical mixing of gas and air.proper cooling and high flame velocity. To obtain the necessarychemiluminescence reaction. burning must take place in the reducing zoneofthe flame. In the normal flame. the sample. which enters with anexcess of oxygen. is converted to an oxide and swept out of the flame inthe oxidizing sheath. Three methods of rapid mechanical mixing of airand hydrogen are used. The principal method is by turbulent flow along asurface and this is augmented by some cross-jet action between thehydrogen gas coming down thru chamber 38 and the partially burned samplecoming t-hru channel 36 and by premixing of the hydrogen-and-air sampledelivered by the first-stage burner. The air sample enters with suchvelocity that excess oxygen is present. The first-stage burner uses upsome of this excess oxygen and the rest of the sample is burned in thereducing flame of the second-stage burner.

Flame variability normally changes the intensity of the flame backgroundlight by a factor of two. with a 5 second or greater time constant. whenusing burners having a flame channel diameter of A inch or greater. Thiseffectively sets the detection sensitivity at a level not lower thanthis background unless some form of compensation is employed. which isnot easily accomplished with a random variable such as flame flicker.Accordingly. action is taken in the present burner to reduce thebackground level of light to the lowest possible intensity and tominimize the effect of flame fluctuations.

The background light cannot be reduced below the level set bychemiluminescence of hydrogen. However. increase of the background bythermal excitation and emission of other substances in the hotter.oxidizing portion of the flame where fuel-air mixing begins can beavoided by excluding this zone from view of the phototube. Increasedlight due to incandescence of heated surfaces may be prevented byadequate cooling of the burner. Cooling is accomplished by thermalconduction through the aluminum body of the burner to a heat sink and issupplemented by circulating water thru the body. Excessive cooling isavoided to prevent the condensation of water vapor formed by thehydrogenoxygen combustion. Cooling is also required to keep the interiorsurfaces which are exposed to the flame below 350 C. to avoiddecomposition of the hydride of phosphorus which produces thecharacteristic green emmission.

It is very difficult to prevent flame flicker but. by increasing flamevelocity. flicker frequency can be increased. With greater than l00 feetper second flow of gas in the flame channel. the flicker-effect timeconstant is reduced below 0.1 second. At a light-chopping frequency of 5cycles per second, dwell time per filter segment is 0.1 second (this iswith a circular filter having two semicircular segments). This isgreater than the average light variation cycle so that these variationsare cancelled to a large extent. Starting with a gas pump of a fixedpumping rate. the rate of flow of the gas in the flame channel can bevaried by varying the diameter of i the gas channel. With the particularpump used. it was found that a flame channel of approximately /4 inchdiameter would provide the desired gas velocity.

In addition to reducing the effect of flame. flicker. the

high velocity flame has other advantages. Of first im-. portance is thefact that interference from sulfur. is:

along the flame channel below the first viewing port and to utilize theproper viewing filter and associated equipment as will be explainedbelow:

Additionally. the blowtorch-like flame confined in a channel burns inany direction. which makes it insensitive to the inclination of theburner. By directing the flame downward as in the present invention.condcn-l sates and aerosols are eliminated more quickly with less effecton flame stability.

Further, the high velocity of the flame makes it much more stable whensubjected to blasts or other sudden pressure changes.

The special-purpose use for which this burner is intended requires aresponse within five seconds when the phosphorus concentration of thesampled air is one microgram per liter or greater. Sincethe phosphorusreacts almost instantaneously in the flame. any delay in. response iscaused primarily by holdup through sorption of the contaminant on theexposed surfaces of the sample intake. In general. this delay becomesexcessive when an air pump is placed in the intake line to forcefeed theburner because of the great increase in surface area resulting from thelocation of the pump at this point. As a consequence.the pump is placedin the exhaust line of the burner (see the system schematic. FIG. 5).This requires that the burner be inclosed. Enclosure of the burnerrequires that internal cavities be minimized to avoid excessive buildupof pressure which would rupture the viewing window or snuff the flame oninitial ignition. Although no firm upper limit may be specified. it hasbeen found desirable to restrict the I cavities to no more than V2 inchdiameter by /2 to 1 inches in length. The dimensions chosen for theparticular embodiment being described have been governed more by theneed to compromise between a high surface-to-volume ratio (to promotebest mixing of fuel and air) and the bore diameter below which the flamewill become, unstable at the flow rates of hydrogen 1.5

liters per minute) and air (2.5 liters per minute) which are used. Bestresults were obtained with the burner chamber between 3/16 and A inchinside diameter. En-

closure of the burner requires. in addition. a burner lighting devicesuch as a sparkplug or electrically heated wire. of which the former isthe more reliable choice.

It should be noted that. to improve speed of response. an. air pump waschosen which has an air-flow capacity much in excess (5 times) theburner requirements; the excess air is burned in the first-stage burner.This brings the air to the second-stage burner more quickly than wouldotherwise have been the case. not only because of faster air flow butalso because the exposed surfaces of the intake lines are more rapidlysaturated with the contaminant.

The presence of a phosphorus-bearing contaminant in the air sample isindicated in the following manner. A light chopper. consisting of alight filter 50 and a motor 56 for rotating the filter 50. is provided.The filter 50 consists of two semicircular sections. one being a greenfilter 52 and the other a blue filter 54. The light filter 50 is placedbetween the viewing port 24 of the burner (see FIG. 5) and a phototube58. Thus. alternate flashes or pulses of green and blue light arereceived by the phototube 58 and are passed through capacitive couplingthrough an amplifier 60 to some sort of indicator62 which may comprise avisual or audible indicator. The speed at which the color filter isrotated gives the pulses a frequency of about 5 cps. A remote indicator64 may also be provided.

The remainder of the system consists of the support system for theburner 10. It includes an exhaust pump 66. a hydrogen supply system 68.and a water cooling system with a pump 70 and reservoir 72.

Although the low background and high velocity of the flame minimizesvariations due to flicker. it does not prevent zero drift due to changesin flame size which are caused by changes in either the quantity of airor hydrogen supplied to the burner 10. To correct for this drift.advantage is taken of the fact that hydrogen emits light ofapproximately equal intensity in both the green and blue portions of thespectrum. By suitable adjustment of the color of the blue and greensections of the light filter 50. the phototube 58 can be made to respondequally to either color of the hydrogen emission and will thereforeresult in a steady d.c. signal from the phototube. The capacitivecoupling of the amplifier 60 will not pass this do signal so that thehydrogen light will give no indication whatever.

However. since the green light from any phosphorus emission is greaterthan the blue light. the alternate pulses will differ in amplitude and adifference signal will be passed through the capacitive coupling.amplified and sent to the indicator 62 which will show the presence ofthe contaminant.

With a second viewing port located in the proper place for asulfur-bearing contaminant and a second color filter and phototubeconnected to the amplifier or to another amplifier and indicator. asdesired. the system can be used for detecting phosphorus and sulfurcontaminants simultaneously. FIG. 6 is a rough sketch showing therelative location of the viewing port 74 for the sulfur emission.

The electronic circuits for the detection system are conventional andwithin the capabilities of any skilled worker in the electronic art andtherefore will not be described herein.

The dimensions for a typical embodiment of the invention are roughly thefollowing:

block: 5 A high X 1% wide X 1 inch deep first-burner inlet channel: Adiam. X 1 /11 inches long first-burner chamber: A diam. X 2% inches longfirst-burner exhaust channel: 1/16 diam. X 5/16 inch long second-burnerchamber: A diam. X 2% inches long flame channel: 1/16 diamv X 2 /8inches long water channel: 3/16 diam. X 5 inches long.

It will be understood that various changes in the details materials. andarrangements of parts (and steps). which have been herein described andillustrated in order to explain the nature of the invention. may be madeby those skilled in the art within the principle and scope of theinvention as expressed in the appended claims.

1 claim:

1. A hydrogen burner for producing a color spectrum from thechemiluminescent burning of contaminantbearing vapors and aerosolscomprising. in combination:

a substantially rectangular block of metal having borings therethroughforming a first burner. a second burner. a flame channel. an ignitionchamber. at least one viewing port and a water channel.

said first burner comprising a transverse channel near the upper end ofsaid block having a hydrogen inlet port at one end thereof and an airinlet port at the other end. a longitudinal burning chamber connectingwith said inlet channel and extending downward therefrom. and atransverse exhaust channel which extends orthogonally from said burningchamber and is narrow in diameter relative to the diameters of saidinlet channel and said burning chamber.

said second burner comprising a longitudinal burning chamber and atransverse ignition chamber. said burning chamber connecting at one endwith said hydrogen inlet port and one end of said first-burner inletchannel and connecting near its other end with said first-burner exhaustchannel. said ignition chamber connecting with said second-burnerchamber at the level of said first-burner exhaust channel and forming avirtual extension thereof to an outer surface of said block.

said flame channel connecting with the other end of said second-burnerchamber and extending downward therefrom. the diameter of said flamechannel being narrow relative to that of said second-burner chamber butincreasing in diameter at its other end to form an exhaust portconnecting with an outer surface of said block. the diameter of theflame channel being designed to provide a high-velocity flow of gastherethrough.

said viewing port comprising an undercut portion extending from asurface of said block to said flame channel in a location which permitsthe chemiluminescent color spectrum of the burning contaminant to beviewed but is sufficiently far from the oxidizing portion of the flamein said second burner to exclude the light from the oxidizing portionfrom view.

said water channel extending longitudinally through said block andhaving an inlet and an outlet port:

a cover for said viewing port comprising a transparent pane and holdingmeans therefor. said holding means being shaped to fit into said viewingport and to be held therein so that said flame channel can be viewedthrough said pane; and

an ignition device seated in said ignition chamber for igniting thegases in said first and second burners.

2. A hydrogen burner as in claim 1. including a second viewing port andassociated cover. said second viewing port being located farther downalong said flame channel at a location at which the chemiluminescentcolor spectrum of a slower-reacting contaminant than the first isvisible.

3. A system for detecting the presence of contaminant-bearing aerosolsand vapors by means of the color spectrum emitted from thechemiluminescent burning thereof comprising. in combination:

a high-velocity-flame hydrogen burner comprising a substantiallyrectangular block of metal having borings therethrough forming a firstburner. a second burner. a flame channel. an ignition chamber. at leastone viewing port and a water channel. said first burner comprising atransverse channel near the upper end of said block having a hydrogeninlet port at one end thereof and an air inlet port at the other end. alongitudinal burning chamber connecting with said inlet channel andextending down-ward therefrom. and a transverse exhaust channel whichextends orthogonally from said burning chamber and is narrow in diameterrelative to the diameters of said inlet channel and said burningchamber. said second burner comprising a longitudinal burning chamberand a transverse ignition chamber. said bunting chamber connecting atone end with said hydrogen inlet port and one end of said first-burnerexhaust channel. said ignition chamber connecting with said secondburnerchamber at the level of said first-burner exhaust channel and forming avirtual extension thereof to an outer surface of said block. said flamechannel connecting with the other end of said second-burner chamber andextending downward therefrom, the diameter of said flame being narrowrelative to that of said second-burner but increasing in diameter at itsother end to form an exhaust port connecting with an outer surface ofsaid block. the diameter of the flame channel being designed to providea high-velocity flow of gas therethrough. said viewing port comprisingan undercut portion extending from a surface of said block to said flamechannel in a location which permits the chemiluminescent color spectrumof the burning contaminant to be viewed but is sufficiently far from theoxidizing portion of the flame in said second burner to exclude thelight from the oxidizing portion from view. said water channel extendinglongitudinally through said block and having an inlet and an outletport. a cover for said viewing port comprising a transparent pane andholding means therefor. said holding means being shaped to fit into saidviewing port and to be held therein so that said flame channel can beviewed through saidpane. and. an ignition device seated in said ignitionchamber for igniting the gases in said first and second,

burners:

means connected to said hydrogen inlet port for supplying hydrogen gasthereto;

means connected to said 'ater inlet and outlet ports for circulatingwater through said water channel;

exhaust means connected to said exhaust port. for pulling air andhydrogen gas through said first and second burners and said flamechannel: and

color detection means arranged to view the light emitted from saidviewing port. said detection means being adapted to provide a signaloutput proportional to the difference in intensity of two colors. I 4. Asystem as in claim 3, wherein said color detection means comprises:

color filter means including a filter consisting of two semi-circles oftranslucent material. each being of a different color for passing onecomponent of the chemiluminescent color spectrum of said contaminantelement. and means for rotating said filter at a predetermined speedwhereby the dwell time per filter segment is greater than the averagelight variation cycle resulting from flame flicker; phototube meansarranged to view light passed by said filter and provide an electricaloutput proportional to the intensity thereof; amplifying means forreceiving the output of said phototube means for amplifying thedifferences in its output caused by differences in intensity of the twocolors transmitted by said filter; and means connected to receive theoutput of said amplifying means for indicating the existence of adifference signal 5. A system as in claim 3, wherein said exhaust meansincludes pump means having the capacity to provide a high-velocity flowof the incoming gases.

6. A system as in claim 4. wherein said two segments 1 of said filterare blue and green. respectively. and are color balanced to provideequal outputs from the color spectrum of a hydrogen flame. and saidviewing port is.

means associated therewith. said second viewing port being locatedfarther down along said flame channel at a point atwhich thechemiluminescent spectrum of a sulfur contaminant is visible.

l l l

1. A HYDROGEN BURNER FOR PRODUCING A COLOR SPECTRUM FROM THECHEMILUMINESCENT BURNING OF CONTAMINANT-BEARING VAPORS AND AEROSOLSCOMPRISING, IN COMBINATION: A SUBSTANTIALLY RECTANGULAR BLOCK OF METALHAVING BORINGS THERETHROUGH FORMING A FIRST BURNER, A SECOND BURNER, AFLAME CHANNEL, AN IGNITION CHAMBER, AT LEAST ONE VIEWING PORT AND AWATER CHANNEL, SAID FIRST BURNER COMPRISING A TRANSVERSE CHANNEL NEARTHE UPPER END OF SAID BLOCK HAVING A HYDROGEN INLET PORT AT ONE ENDTHEREOF AND AN AIR INLET PORT AT THE OTHER END, A LONGITUDINAL BURNINGCHAMBER CONNECTING WITH SAID INLET CHANNEL AND EXTENDING DOWNWARDTHEREFROM, AND A TRANSVERSE EXHAUST CHANNEL WHICH EXTENDS ORTHOGONALLYFROM SAID BURNING CHAMBER AND IS NARROW IN DIAMETER RELATIVE TO THEDIAMETERS OF SAID OF SAID INLET CHANNEL AND SAID BURNING CHAMBER, SAIDSECOND BURNER COMPRISING A LOGITUDINAL BURNING CHAMBER AND A TRANSVERSEIGNITION CHAMBER, SAID BURNING CHAMBER CONNECTING AT ONE END WITH SAIDHYDROGEN INLET PORT AND END OF SAID FIRST-BURNER INLET CHANNEL ANDCONNECTING NEAR ITS OTHER END WITH SAID FIRST-BURNER EXHAUST CHANNEL ANDFORMING A VIRTUAL EXTENSION THEREOF SECOND-BURNER CHAMBER AT THE LEVELOF SAID FIRST-BURNER EXHAUST CHANNEL AND FORMING A VIRTUAL EXTENSIONTHEREOF TO AN OUTER SURFACE OF SAID BLOCK. SAID FLAME CHANNEL CONNECTINGWITH THE OTHER END OF SAID SECOND-BURNER CHAMBER AND EXTENDING DOWNWARDTHEREFROM, THE DIAMETER OF SAID FLAME CHANNEL BEING NARROW
 2. A hydrogenburner as in claim 1, including a second viewing port and associatedcover, said second viewing port being located farther down along saidflame channel at a location at which the chemiluminescent color spectrumof a slower-reacting contaminant than the first is visible.
 3. A SYSTEMFOR DETECTING THE PRESENCE OF CONTAMINANTBEARING AEROSOLS AND VAPORS BYMEANS OF THE COLOR SPECTRUM EMMITTED FROM THE CHEMILUMINESCENT BURNINGTHEREOF COMPRISING, IN COMBINATION: A HIGH-VELOCITY-FLAME HYDROGENBURNER COMPRISING A SUBSTANTIALLY RECTANGULAR BLOCK OF METAL HAVINGBORINGS THERETHROUGH FORMING A FIRST BURNER, A FLAME CHANNEL, ANDIGNITION CHAMBER, AT LEAST ONE VIEWING PORT AND A WATER CHANNEL, SAIDFIRST BURNER COMPRISING A TRANSVERSE CHANNEL NEAR THE UPPER END OF SAIDBLOCK HAVING A HYDROGEN INLET PORT AT ONE END THEREOF AND AN AIR INLETPORT AT THE OTHER END, A LONGITUDINAL BURNING CHAMBER CONNECTING WITHSAID INLET CHANNEL AND EXTENDING DOWN-WARD THEREFROM, AND A TRANSVERSEEXHAUST CHANNEL WHICH EXTENDS ORTHOGONALLY FROM SAID BURNING CHAMBER ANDIS NARROW IN DIAMETER RELATIVE TO THE DIAMETERS OF SAID INLET CHANNELAND SAID BURNING CHAMBER, SAID SECOND BURNER COMPRISING A LONGITUDINALBURNING CHAMBER AND A TRANSVERSE IGNITION CHAMBER, SAID BURNING CHAMBERCONNECTING AT ONE END WITH SAID HYDROGEN INLET PORT AND ONE END OF SAIDFIRST-BURNER EXHAUST CHANNEL, SAID IGNITION CHAMBER CONNECTING WITH SAIDSECOND-BURNER CHAMBER AT LEVEL OF SAID FIRST-BURNER EXHAUST CHANNEL ANDFORMING A VIRTUAL EXTENSION THEREOF TO AN OUTER SURFACE OF SAID BLOCK,SAID FLAME CHANNEL CONNECTING WITH THE OTHER END OF SAID SECOND-BURNERCHAMBER AND EXTENDING DOWNWARD THEREFROM, THE DIAMETER OF SAID FLAMEBEING NARROW RELATIVE TO THAT OF SSAID SECOND-BURNER BUT INCREASING INDIAMETER AT ITS OTHER END EXHAUST PORT CONNECTING WITH AN OUTER SURFACETO SAID BLOCK, THE DIAMETER OF THE FLAME CHANNEL BEING DESIGNED TOPROVIDE A HIGH-VELOCITY FLOW OF GAS THERETHROUGH, SAID VIEWING PORTCOMPRISING AN UNDERCUT PORTION EXTENDING FROM A SURFACE OF SAID BLOCK TOSAID FLAME CHANNEL IN A LOCATION WHICH PERMITS THE CHEMILUMINESCENTCOLOR SPECTRUM OF THE BURNING CONTAMINANT TO BE VIEWED BUT ISSUFFICIENTLY FAR FROM THE OXIDIZING PORTION OF THE FLAME IN SAID SECONDBURNER TO EXCLUDE THE LIGHT FORM THE OXIDIZING PORTION FROM VIEW, SAIDWATER CHANNEL EXTENDING LONGITUDINALLY THROUGH SAID BLOCK AND HAVING ANINLET AND AN OUTLET PORT, A COVER FOR SAID VIEWING PORT COMPRISING ATRANSPARENT PANE AND HOLDING MEANS THEREOF, SAID HOLDING MEANS BEINGSHAPED TO FIT INTO SAID VIEWING PORT AND TO BE HELD THEREIN SO THAT SAIDFLAME CHANNEL CAN BE VIEWED THROUGH SAID PANE, AND AN IGNITION DEVICESSEATED IN SAID IGNITION CHAMBER FOR IGNITING THE GASES IN SAID FIRST ANDSECOND BURNERS; MEANS CONNECTED TO SAID HYDROGEN INLET PORT FORSUPPLYING HYDROGEN GAS THERETO; MEANS CONNECTED TO SAID WATER INLET ANDOUTLET PORTS FOR CIRCULATING WATER THROUGH SAID WATER CHANNEL; EXHAUSTMEANS CONNECTED TO SAID EXHAUST PORT FOR PULLING AIR AND HYDROGEN GASTHROUGH SAID FIRST AND SECOND BURNERS AND SAID FLAME CHANNEL; AND COLORDETECTION MEANS ARRANGED TO VIEW THE LIGHT EMITTED FROM SAID VIEWINGPORT, SAID DETECTION MEANS BEING ADAPTED TO PROVIDE A SIGNAL OUTPUTPROPORTIONAL TO THE DIFFERENCE IN INTENSITY OF TWO COLORS.
 4. A systemas in claim 3, wherein said color detection means comprises: colorfilter means including a filter consisting of two semi-circles oftranslucent material, each being of a different color for passing onecomponent of the chemiluminescent color spectrum of said contaminantelement, and means for rotating said filter at a predetermined speedwhereby the dwell time per filter segment is greater than the averagelight variation cycle resulting from flame flicker; phototube meansarranged to view light passed by said filter and provide an electricaloutput proportional to the intensity thereof; amplifying means forreceiving the output of said phototube means for amplifying thedifferences in its output caused by differences in intensity of the twocolors transmitted by said filter; and means connected to receive theoutput of said amplifying means for indicating the existence of adifference signal.
 5. A system as in claim 3, wherein said exhaust meansincludes pump means having the capacity to provide a high-velocity flowof the incoming gases.
 6. A system as in claim 4, wherein said twosegments of said filter are blue and green, respectively, and are colorbalanced to provide equal outputs from the color spectrum of a hydrogenflame, and said viewing port is located at a point along the flamechannel where the chemiluminescent spectrum of a phosphorus contaminantis visible.
 7. A system as in claim 4, including a second viewing portand associated cover, and second color detection means associatedtherewith, said second viewing port being located farther down alongsaid flame channel at a point at which the chemiluminescent spectrum ofa sulfur contaminant is visible.